13 September 2009

4 minute read

In these difficult economic times, it is important to optimise cow management and housing as much as possible to improve milk production efficiency. Some aspects of cow comfort, such as quiet and calm handling, don’t cost any money.

The Dairy Extension research team, has been involved in investigating the association between cow well-being and the cow’s environment, especially as it relates to lameness prevalence. Lameness is the most important animal welfare issue in our industry and also of great economic significance. Each case of lameness is estimated to cost approximately $404 (C. Guard, Cornell University).

Research showed that cows housed in an alternative bedded pack housing system known as compost barns have better feet and leg health due to the soft resting surface available to them in that system. There is also a better social environment for the cows. However, reduced availability and high cost of sawdust for bedding have limited the use of this housing system to a relatively small number of producers. Recent work by the research group showed that there are alternatives to sawdust, such as processed straw, processed corn cobs, wood chip fines, strawdust, and other locally available dry, finely processed, structural materials. Some producers use a compost bedded pack as a special needs pen for fresh and lame cows, and this is especially useful for those who have freestall barns with mattresses. Research conducted in a large sample of dairies in Minnesota showed that cows housed in freestall barns with mattresses have greater lameness prevalence than cows housed in sand-based stalls (28 per cent vs. 17 per cent prevalence).

The low availability and high cost of organic bedding materials in Minnesota has led to investigations in the use of recycled manure solids for bedding freestalls. In August, the research team started a two-year project to learn what factors are associated with somatic cell counts and mastitis incidence in herds currently using manure solids in the upper Midwest. They are also evaluating other aspects of animal welfare in these facilities to see how it compares with other types of bedding surfaces investigated in recent years. Their goal is to learn how to optimise the use of solids for good cow health and comfort. What would be better than having cows produce their own bedding? Not having to depend on external sources for bedding is a great option, from both an economic and environmental perspective.

Another area of research the research team are currently working on is the field use of thermal imaging for early detection of lameness, so producers could more easily intervene before cows become severely lame. Loss of production, risk of culling and animal discomfort increase substantially when lesions become more severe. If the problem can be corrected earlier with preventative trimming, cow productivity and well-being will improve.

Heat stress is another welfare concern and it can contribute not only to milk production loss, but also poor reproduction and increased lameness prevalence. A new housing system known as low profile cross-ventilated freestall barn is being evaluated. These barns are completely enclosed and have a line of fans on one side that blows air out of the barn whereas the other side of the barn has a wall of evaporative cooling pads. When water is dripped down the pads and air is drawn through them into the barn, the air is evaporatively cooled. Preliminary results were presented of the descriptive phase of this study at the recent Dairy Science meetings. When cross-ventilated was compared to naturally ventilated freestall barns (all bedded with sand), very similar hygiene scores (both averaged 2.8), body condition scores (2.99 and 2.97, respectively), hock lesion prevalence (31 and 2 per cent, respectively) were found and no significant difference in lameness prevalence (14.3 and 17.8 per cent, respectively). However, older cows in cross-ventilated barns tended to have lower lameness prevalence than cows in naturally ventilated barns (15 vs. 23 per cent). Also observed was better cow comfort index in the summer for cows housed in cross-ventilated barns (85 vs. 77 per cent, respectively). It is possible that the better heat abatement provided by the cross-ventilation helped improve lying time during the summer and consequently tended to reduce lameness.

These are some brief examples of the research on cow comfort that have been conducted at the University of Minnesota. The bottom line is that various aspects of housing can influence cow comfort, and therefore cow health and productivity. Marcia Endres, Extension Dairy Scientist would like to thank all the dairy producers in Minnesota and neighboring states who have kindly agreed to participate in the studies, helping to make the research efforts possible. In addition, thanks to visiting researcher Kadir Orman from Turkey, and graduate students Abby Barberg, Luis Espejo, Adam Husfeldt, Karen Lobeck and Erika Shane for their help with the studies mentioned in this article.